Re: [PATCH] mm, kasan: don't poison boot memory | linux-arm-kernel

(off-list ancestor, not in this archive)

On Thu, Feb 25, 2021 at 11:31:04AM -0500, George Kennedy wrote:

On 2/25/2021 11:07 AM, Mike Rapoport wrote:
On Thu, Feb 25, 2021 at 10:22:44AM -0500, George Kennedy wrote:
On 2/24/2021 5:37 AM, Mike Rapoport wrote:
Applied just your latest patch, but same failure.

I thought there was an earlier comment (which I can't find now) that stated
that memblock_reserve() wouldn't reserve the page, which is what's needed
here.
Actually, I think that memblock_reserve() should be just fine, but it seems
I'm missing something in address calculation each time.

What would happen if you stuck

	memblock_reserve(0xbe453000, PAGE_SIZE);

say, at the beginning of find_ibft_region()?
Added debug to your patch and this is all that shows up. Looks like the
patch is in the wrong place as acpi_tb_parse_root_table() is only called for
the RSDP address.
Right, but I think it parses table description of the other tables and
populates local tables with them.
I think the problem is with how I compare the signatures, please see below

[    0.064317] ACPI: Early table checksum verification disabled
[    0.065437] XXX acpi_tb_parse_root_table: rsdp_address=bfbfa014
[    0.066612] ACPI: RSDP 0x00000000BFBFA014 000024 (v02 BOCHS )
[    0.067759] ACPI: XSDT 0x00000000BFBF90E8 00004C (v01 BOCHS BXPCFACP
00000001      01000013)
[    0.069470] ACPI: FACP 0x00000000BFBF5000 000074 (v01 BOCHS BXPCFACP
00000001 BXPC 00000001)
[    0.071183] ACPI: DSDT 0x00000000BFBF6000 00238D (v01 BOCHS BXPCDSDT
00000001 BXPC 00000001)
[    0.072876] ACPI: FACS 0x00000000BFBFD000 000040
[    0.073806] ACPI: APIC 0x00000000BFBF4000 000090 (v01 BOCHS BXPCAPIC
00000001 BXPC 00000001)
[    0.075501] ACPI: HPET 0x00000000BFBF3000 000038 (v01 BOCHS BXPCHPET
00000001 BXPC 00000001)
[    0.077194] ACPI: BGRT 0x00000000BE49B000 000038 (v01 INTEL EDK2    
00000002      01000013)
[    0.078880] ACPI: iBFT 0x00000000BE453000 000800 (v01 BOCHS BXPCFACP
00000000      00000000)
[    0.080588] ACPI: Local APIC address 0xfee00000

diff --git a/drivers/acpi/acpica/tbutils.c b/drivers/acpi/acpica/tbutils.c
index dfe1ac3..603b3a8 100644
--- a/drivers/acpi/acpica/tbutils.c
+++ b/drivers/acpi/acpica/tbutils.c
@@ -7,6 +7,8 @@
  *
*****************************************************************************/

+#include <linux/memblock.h>
+
 #include <acpi/acpi.h>
 #include "accommon.h"
 #include "actables.h"
@@ -232,6 +234,8 @@ struct acpi_table_header *acpi_tb_copy_dsdt(u32
table_index)
     acpi_status status;
     u32 table_index;

+printk(KERN_ERR "XXX acpi_tb_parse_root_table: rsdp_address=%llx\n",
rsdp_address);
+
     ACPI_FUNCTION_TRACE(tb_parse_root_table);

     /* Map the entire RSDP and extract the address of the RSDT or XSDT */
@@ -339,6 +343,22 @@ struct acpi_table_header *acpi_tb_copy_dsdt(u32
table_index)
             acpi_tb_parse_fadt();
         }

+        if (ACPI_SUCCESS(status) &&
+            ACPI_COMPARE_NAMESEG(&acpi_gbl_root_table_list.
+                     tables[table_index].signature,
+                     ACPI_SIG_IBFT)) {
We have:

include/acpi/actbl1.h:#define ACPI_SIG_IBFT           "IBFT"    /* iSCSI Boot Firmware Table */

and the BIOS uses "iBFT", so we need to loop over possible signature
variants like iscsi_ibft_find does.

Do you mind replacing ACPI_SIG_IBFT with "iBFT" and try again?

+            struct acpi_table_header *ibft;
+            struct acpi_table_desc *desc;
+
+            desc = &acpi_gbl_root_table_list.tables[table_index];
+            status = acpi_tb_get_table(desc, &ibft);
+            if (ACPI_SUCCESS(status)) {
+printk(KERN_ERR "XXX acpi_tb_parse_root_table(calling memblock_reserve()):
addres=%llx, ibft->length=%x\n", address, ibft->length);
+                memblock_reserve(address, ibft->length);
+                acpi_tb_put_table(desc);
+            }
+        }
+
 next_table:

         table_entry += table_entry_size;


[   30.308229] iBFT detected..
[   30.308796]
==================================================================
[   30.308890] BUG: KASAN: use-after-free in ibft_init+0x134/0xc33
[   30.308890] Read of size 4 at addr ffff8880be453004 by task swapper/0/1
[   30.308890]
[   30.308890] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.11.0-f9593a0 #12
[   30.308890] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
0.0.0 02/06/2015
[   30.308890] Call Trace:
[   30.308890]  dump_stack+0xdb/0x120
[   30.308890]  ? ibft_init+0x134/0xc33
[   30.308890]  print_address_description.constprop.7+0x41/0x60
[   30.308890]  ? ibft_init+0x134/0xc33
[   30.308890]  ? ibft_init+0x134/0xc33
[   30.308890]  kasan_report.cold.10+0x78/0xd1
[   30.308890]  ? ibft_init+0x134/0xc33
[   30.308890]  __asan_report_load_n_noabort+0xf/0x20
[   30.308890]  ibft_init+0x134/0xc33
[   30.308890]  ? write_comp_data+0x2f/0x90
[   30.308890]  ? ibft_check_initiator_for+0x159/0x159
[   30.308890]  ? write_comp_data+0x2f/0x90
[   30.308890]  ? ibft_check_initiator_for+0x159/0x159
[   30.308890]  do_one_initcall+0xc4/0x3e0
[   30.308890]  ? perf_trace_initcall_level+0x3e0/0x3e0
[   30.308890]  ? unpoison_range+0x14/0x40
[   30.308890]  ? ____kasan_kmalloc.constprop.5+0x8f/0xc0
[   30.308890]  ? kernel_init_freeable+0x420/0x652
[   30.308890]  ? __kasan_kmalloc+0x9/0x10
[   30.308890]  ? __sanitizer_cov_trace_pc+0x21/0x50
[   30.308890]  kernel_init_freeable+0x596/0x652
[   30.308890]  ? console_on_rootfs+0x7d/0x7d
[   30.308890]  ? __sanitizer_cov_trace_pc+0x21/0x50
[   30.308890]  ? rest_init+0xf0/0xf0
[   30.308890]  kernel_init+0x16/0x1d0
[   30.308890]  ? rest_init+0xf0/0xf0
[   30.308890]  ret_from_fork+0x22/0x30
[   30.308890]
[   30.308890] The buggy address belongs to the page:
[   30.308890] page:0000000001b7b17c refcount:0 mapcount:0
mapping:0000000000000000 index:0x1 pfn:0xbe453
[   30.308890] flags: 0xfffffc0000000()
[   30.308890] raw: 000fffffc0000000 ffffea0002ef9788 ffffea0002f91488
0000000000000000
[   30.308890] raw: 0000000000000001 0000000000000000 00000000ffffffff
0000000000000000
[   30.308890] page dumped because: kasan: bad access detected
[   30.308890] page_owner tracks the page as freed
[   30.308890] page last allocated via order 0, migratetype Movable,
gfp_mask 0x100dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), pid 204, ts 28121288605
[   30.308890]  prep_new_page+0xfb/0x140
[   30.308890]  get_page_from_freelist+0x3503/0x5730
[   30.308890]  __alloc_pages_nodemask+0x2d8/0x650
[   30.308890]  alloc_pages_vma+0xe2/0x560
[   30.308890]  __handle_mm_fault+0x930/0x26c0
[   30.308890]  handle_mm_fault+0x1f9/0x810
[   30.308890]  do_user_addr_fault+0x6f7/0xca0
[   30.308890]  exc_page_fault+0xaf/0x1a0
[   30.308890]  asm_exc_page_fault+0x1e/0x30
[   30.308890] page last free stack trace:
[   30.308890]  free_pcp_prepare+0x122/0x290
[   30.308890]  free_unref_page_list+0xe6/0x490
[   30.308890]  release_pages+0x2ed/0x1270
[   30.308890]  free_pages_and_swap_cache+0x245/0x2e0
[   30.308890]  tlb_flush_mmu+0x11e/0x680
[   30.308890]  tlb_finish_mmu+0xa6/0x3e0
[   30.308890]  exit_mmap+0x2b3/0x540
[   30.308890]  mmput+0x11d/0x450
[   30.308890]  do_exit+0xaa6/0x2d40
[   30.308890]  do_group_exit+0x128/0x340
[   30.308890]  __x64_sys_exit_group+0x43/0x50
[   30.308890]  do_syscall_64+0x37/0x50
[   30.308890]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   30.308890]
[   30.308890] Memory state around the buggy address:
[   30.308890]  ffff8880be452f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ff ff
[   30.308890]  ffff8880be452f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ff ff
[   30.308890] >ffff8880be453000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ff ff
[   30.308890]                    ^
[   30.308890]  ffff8880be453080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ff ff
[   30.308890]  ffff8880be453100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ff ff
[   30.308890]
==================================================================

George
-- 
Sincerely yours,
Mike.

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